6.3 Trees

tree-view
is a pane that displays a hierarchical list of items. Each item may optionally have an image and a checkbox.

Callbacks can be specified as for other choice classes. Additionally you can control how the nodes of the tree are expanded, and there is
delete-item-callback
available for use when the user presses the
Delete
key.

Tree views are used in the LispWorks IDE, for example in the
Output Data
view of the Tracer tool and the
Backtrace
area of the Debugger and Stepper tools.